Definitions

Length of border with Russia:
Length in kilometers of each country's border with Russia. China, which has a border with Russia of 3,645 km, is not included. Russia has international borders with 16 countries, and a total land border of 20,241 kilometres (12,577 mi), making it the second-longest one of any country in the world.

Number of maritime boundary neighbours:
Number of states and territories with which each country shares a maritime border. Two countries separated from each other by a body of water have a maritime border with each other.